CAN COMMUNICATION SYSTEM(w/o Central Gateway ECU) Check CAN Bus Lines for Short Circuit (LHD Models)

DESCRIPTION

There may be a short circuit between the V bus main lines and/or CAN branch lines when the resistance between terminals 6 (CANH) and 14 (CANL) of the DLC3 is below 54 Ω.

Symptom Trouble Area
Resistance between terminals 6 (CANH) and 14 (CANL) of DLC3 is below 54 Ω.

  • Short in CAN main bus line

  • Short in CAN branch line

  • Power management control ECU

  • ECM

  • Main body ECU (Multiplex network body ECU)

  • Meter circuit plate

  • Brake booster with master cylinder assembly (Skid control ECU)

  • Spiral cable with sensor sub-assembly (Steering angle sensor)

  • Yaw rate sensor

  • Power steering ECU assembly

  • Airbag ECU assembly

  • Transmission control ECU assembly

  • Certification ECU (Smart key ECU assembly)

  • Navigation ECU sub-assembly*1

  • Radio and display receiver assembly*2

  • CAN No. 1 junction connector

  • CAN No. 2 junction connector

  • CAN No. 3 junction connector

*1: for Navigation receiver type

*2: for Radio and display type

WIRING DIAGRAM

A005B7BE09
A005DSGE14

CAUTION / NOTICE / HINT

Note


  • Before measuring the resistance of the CAN bus, turn the power switch off and leave the vehicle for 1 minute or more without operating the key, switches or opening or closing the doors. After that, disconnect the cable from the negative (-) auxiliary battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.

  • After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work Click here.

  • Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output Click here.

  • After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.

  • DTC check procedure: Turn the power switch on (IG), turn the cruise control system on using the cruise control switch (ON/OFF switch), wait at least 60 seconds, and then drive the vehicle at a speed of 50 km/h (31 mph) or more for at least 1.72 seconds.

  • After the repair, perform CAN Bus Check and check that all the ECUs and sensors connected to the CAN communication system are displayed Click here.

Tech Tips


  • Operating the power switch, any other switches or a door triggers related ECU and sensor communication on the CAN. This communication will cause the resistance value to change.

  • Even after DTCs are cleared, if a DTC is stored again after driving the vehicle for a while, the malfunction may be occurring due to vibration of the vehicle. In such a case, wiggling the ECUs or wire harness while performing the inspection below may help determine the cause of the malfunction.

PROCEDURE


  1. CHECK FOR SHORT IN CAN BUS LINES (ECM)


    1. Disconnect the cable from the negative (-) auxiliary battery terminal.

    2. A005DLLE01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to ECM)

      Disconnect the ECM connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      A57-13 (CANH) - A57-5 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

    OK

    REPLACE ECM Click here

    NG

  2. CHECK FOR SHORT IN CAN BUS LINES (METER CIRCUIT PLATE)


    1. Reconnect the ECM connector.

    2. A005DJFE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Meter Circuit Plate)

      Disconnect the meter circuit plate connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      L27-19 (CANH) - L27-20 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

    OK

    REPLACE METER CIRCUIT PLATE Click here

    NG

  3. CHECK FOR SHORT IN CAN BUS LINES (CAN NO. 2 J/C)


    1. Reconnect the meter circuit plate connector.

    2. A005ETNE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to CAN No. 2 Junction Connector)
      *b to CAN No. 3 Junction Connector
      *c to CAN No. 1 Junction Connector
      *d to Certification ECU (Smart Key ECU Assembly)
      *e to Spiral Cable with Sensor Sub-assembly (Steering Angle Sensor)

      Disconnect the wire harness connector from the CAN No. 2 junction connector (instrument panel connector holder left side).

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      L94-2 (CANH) - L94-1 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω CAN No. 3 junction connector
      L94-5 (CANH) - L94-4 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω CAN No. 1 junction connector
      L94-8 (CANH) - L94-7 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Certification ECU (Smart key ECU assembly)
      L94-11 (CANH) - L94-10 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Spiral cable with sensor sub-assembly (Steering angle sensor)
      Result
      Result Proceed to
      OK A
      NG (CAN No. 1 junction connector main line) B
      NG (CAN No. 3 junction connector main line) C
      NG (ECU or sensor branch line) D

    B

    CHECK FOR SHORT IN CAN BUS LINES (CAN NO. 1 J/C) Click here

    C

    CHECK FOR SHORT IN CAN BUS LINES (CAN NO. 3 J/C) Click here

    D

    CHECK FOR SHORT IN CONNECTED COMPONENT (ECU, SENSOR) Click here

    A

  4. CHECK FOR SHORT IN CAN BUS LINES (CAN NO. 2 J/C)


    1. Disconnect the wire harness connector from the CAN No. 2 junction connector (instrument panel connector holder right side).

    2. A005C3RE03
      Text in Illustration
      *a

      Front view of wire harness connector

      (to CAN No. 2 Junction Connector)
      *b to Power Steering ECU Assembly
      *c to Yaw Rate Sensor
      *d to Airbag ECU Assembly
      *e

      • to Navigation ECU Sub-assembly*1

      • to Radio and Display Receiver Assembly*2
      *f to DLC3

      Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      L95-2 (CANH) - L95-3 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Power steering ECU assembly
      L95-5 (CANH) - L95-6 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Yaw rate sensor
      L95-8 (CANH) - L95-9 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Airbag ECU assembly
      L95-11 (CANH) - L95-12 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher

      • Navigation ECU sub-assembly*1

      • Radio and display receiver assembly*2
      L95-14 (CANH) - L95-15 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 1 MΩ or higher DLC3

      *1: for Navigation receiver type

      *2: for Radio and display type

      *1: for Navigation receiver type

      *2: for Radio and display type

      Result
      Result Proceed to
      OK A
      NG (ECU or sensor branch line) B
      NG (DLC3 branch line) C

    A

    REPLACE CAN NO. 2 JUNCTION CONNECTOR

    B

    CHECK FOR SHORT IN CONNECTED COMPONENT (ECU, SENSOR) Click here

    C

    REPAIR OR REPLACE CAN BRANCH LINE CONNECTED TO DLC3

  5. CHECK FOR SHORT IN CAN BUS LINES (CAN NO. 1 J/C)


    1. A005DC3E03
      Text in Illustration
      *a

      Front view of wire harness connector

      (to CAN No. 1 Junction Connector)
      *b to Main Body ECU (Multiplex Network Body ECU)
      *c to CAN No. 2 Junction Connector

      Disconnect the wire harness connector from the CAN No. 1 junction connector (instrument panel wire side).

    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      L132-5 (CANH) - L132-11 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Main body ECU (Multiplex network body ECU)
      L132-6 (CANH) - L132-12 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 1 MΩ or higher CAN No. 2 junction connector
      Result
      Result Proceed to
      OK A
      NG (CAN No. 2 junction connector main line) B
      NG (ECU or sensor branch line) C

    B

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (CAN NO. 2 J/C - CAN NO. 1 J/C)

    C

    CHECK FOR SHORT IN CONNECTED COMPONENT (ECU, SENSOR) Click here

    A

  6. CHECK FOR SHORT IN CAN BUS LINES (CAN NO. 1 J/C)


    1. Disconnect the wire harness connector from the CAN No. 1 junction connector (engine room main wire side).

    2. A005B92E02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to CAN No. 1 Junction Connector)
      *b to ECM
      *c to Brake Booster with Master Cylinder Assembly (Skid Control ECU)

      Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      A67-1 (CANH) - A67-7 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω ECM
      A67-2 (CANH) - A67-8 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Brake booster with master cylinder assembly (Skid control ECU)
      Result
      Result Proceed to
      OK A
      NG (ECM main line) B
      NG (ECU or sensor branch line) C

    A

    REPLACE CAN NO. 1 JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (CAN NO. 1 J/C - ECM)

    C

    CHECK FOR SHORT IN CONNECTED COMPONENT (ECU, SENSOR) Click here

  7. CHECK FOR SHORT IN CAN BUS LINES (CAN NO. 3 J/C)


    1. Disconnect the wire harness connector from the CAN No. 3 junction connector (instrument panel wire side).

    2. A005BAZE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to CAN No. 3 Junction Connector)
      *b to Power Management Control ECU
      *c to CAN No. 2 Junction Connector
      *d to Meter Circuit Plate

      Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      L133-4 (CANH) -L133-10 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Power management control ECU
      L133-5 (CANH) - L133-11 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 1 MΩ or higher CAN No. 2 junction connector
      L133-6 (CANH) - L133-12 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω Meter circuit plate
      Result
      Result Proceed to
      OK A
      NG (CAN No. 2 junction connector main line) B
      NG (Meter circuit plate main line) C
      NG (ECU or sensor branch line) D

    B

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (CAN NO. 2 J/C - CAN NO. 3 J/C)

    C

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (CAN NO. 3 J/C - METER CIRCUIT PLATE)

    D

    CHECK FOR SHORT IN CONNECTED COMPONENT (ECU, SENSOR) Click here

    A

  8. CHECK FOR SHORT IN CAN BUS LINES (CAN NO. 3 J/C)


    1. Disconnect the wire harness connector from the CAN No. 3 junction connector (engine room main wire side).

    2. A005C0QE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to CAN No. 3 Junction Connector)
      *b to Transmission Control ECU Assembly

      Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      A68-1 (CANH) - A68-7 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Transmission control ECU assembly

    OK

    REPLACE CAN NO. 3 JUNCTION CONNECTOR

    NG

  9. CHECK FOR SHORT IN CONNECTED COMPONENT (ECU, SENSOR)


    1. Reconnect all wire harness connectors (CAN No. 1 junction connector, CAN No. 2 junction connector and CAN No. 3 junction connector).

    2. Disconnect the connector that includes terminals CANH and CANL from the ECU (or sensor) to which the short circuited branch line is connected Click here.

    3. A005A0KE01
      Text in Illustration
      *1 DLC3

      Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      L61-6 (CANH) - L61-14 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 54 to 69 Ω

      Tech Tips


      • If the resistance becomes normal (between 54 and 69 Ω) when the connector is disconnected from the ECU (or sensor), there may be a short in the ECU (or sensor).

      • If the resistance does not become normal (between 54 and 69 Ω) when the connector is disconnected from the ECU (or sensor), repair or replace the short circuited branch line or connector.


    OK

    REPLACE CORRESPONDING ECU OR SENSOR

    NG

    REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR BUS LINE OR CONNECTOR